Prevalence of consumption of mechanically separated meat, consumer profile, nutrient intake and food choices among manufacturing workers in Northeastern Brazil

Mechanically separated meat (MSM) is widely used in the food industry, however, there is a lack of studies on its consumption in populations. The objective of this study was to identify the frequency and amount of MSM consumption, factors associated with MSM consumption, nutrient intake and preferential choice of food groups among MSM consumers. This was an observational, cross-sectional prospective study based on a probability sample of manufacturing workers, conducted in Brazil. Logistic and linear multiple regression with robust standard errors were used. 921 workers from 33 manufacturing companies were studied, with an average age of 38.2 ± 10.7 years, 55.9% males. MSM products are consumed by 28.8% and represent in average 10% of total daily caloric intake, and 47.3% of the daily kcal from ultra-processed products. Younger age and greater waist circumference are associated with MSM consumption. Younger age and lesser educational level are associated with increased contribution of MSM to total daily kcal intake. MSM consumers have greater consumption of energy, fats, carbohydrates and sodium. Their dietary patterns are characterized by lower consumption of in natura and minimally processed foods, such as tubers and roots, fruits, white and red meat, and eggs and greater consumption of ultra-processed foods and beverages.

www.nature.com/scientificreports/and beverages, non-metallic minerals, and textiles) corresponding to the industries with greater representation in the state.
For the first sampling stage, manufacturing companies were selected in each combination of strata levels, in a number proportional to the total number of companies in the state in that combination of strata, by simple random sampling from a sampling grid provided by the federation of state industries (FIERN).In the second sampling stage, a fixed number of workers from each company recruited in the first stage was selected by simple random sampling, using a computer random number generator, from listings of workers provided by the human resources departments of each company.
All companies in the state from the three mentioned sectors of activity that agreed in written to participate in the research were eligible for the study.The inclusion criteria for workers were: over 18 years old with an effective employment relationship with the company.Pregnant women, temporary employees, interns and employees on probationary periods were excluded from the research.
The research was approved by the Research Ethics Committee of the Hospital Universitário Onofre Lopes (authorization number 2.198.545/2017) and carried out in accordance with the Declaration of Helsinki.All participants gave informed consent in writing.

Investigation
In the preparation of the field survey, each visit of the research team was scheduled with each company to occur between Tuesdays and Saturdays.The workers that were previously selected were approached during lunch time and invited to participate in the research.After signing the informed consent form, biodemographic data (age, sex, marital status, education, income, participation in in-house training programs) were recorded and food consumption was assessed using the 24 h dietary recall method (24HR).For the application of the 24HR, the interviewers used the Multiple Pass Methods-MPM, which helps the interviewee to remember the foods consumed the day before the interview and, therefore, minimizes errors in food consumption measurements.This Method is divided into stages, which include a list of the foods consumed, time and place of the meal, detailed description of the quantities of the food (in household measurements), preparation and cooking methods, among other aspects 26 .
Body mass index (BMI), defined by weight in kg divided by squared height in meters, was measured with a digital scale (Inner Scan, Tanita Corp., Tokyo, Japan) and a body height meter (Sanny, São Bernardo do Campo, SP, Brazil).Waist circumference (WC), measured at the midpoint between the lower edge of the last rib and the iliac crest, was measured with a tape meter (Cescorf, Ltda, Porto Alegre, RS, Brazil).The measurements were performed according to the guidelines of the Brazilian Alimentary and Nutritional Surveillance System (SISVAN) 27 .

Characterization of food consumption
The descriptions of food consumption extracted from the 24HR obtained from home measurements were quantified in units of weight and volume, using previously established references (direct weighing of food, photographic records and specific manuals for this purpose 28 .The analysis of the nutritional composition of workers' food consumption was carried out using reference Food Composition Tables [29][30][31] supplemented, when necessary, with information from food labels.
The foods registered in 24HR were classified in two ways: according to the NOVA 32 group and according to the food group, following the classification of food groups in the Food Guide for the Brazilian Population, which considers biological, physicochemical, organoleptic and dietary characteristics, aggregating foods into sets that have similar culinary uses and nutritional profiles 33,34 .Then, the sets defined by the Food Guide were disaggregated into 44 food groups, based on the diversity of foods and preparations referred to in the 24HR.Most freshly prepared foods, which include items from different food groups, were described in their ingredients, defining quantities based on a Technical Preparation Sheet.A small number of freshly prepared mixed foods, based mainly on fresh and/or minimally processed foods, typical of Brazilian cuisine, were classified in the group of foods with the highest contribution of ingredients.Detailed information about the criteria used for this classification was published in another study 35 .

Statistical analysis
The svy suite of commands of the Stata ® 15.1 statistical software (Stata Corporation, College Station, TX, USA) was used for data analysis.The statistical analysis considered the stratification by company size and activity sector, the two-stage sampling plan with companies as the primary sampling units and the workers nested within companies.All analyses were weighted, with sampling weights computed according to the survey plan, a finite population correction was included in the calculations, and robust standard errors were used.Unless otherwise stated, the displayed results are population estimates, not sample statistics, and point estimates with 95% confidence intervals (95%CI) are presented throughout.Associations of consumption of MSM with binary and continuous worker variables were analyzed with logistic regression and multiple linear regression, respectively.Differences in nutrient and food groups consumption between MSM consumers and non-consumers were analyzed with multiple linear regression.A p-value < 0.05 was considered evidence of statistical significance.

Results
From September 2017 to July 2018, 921 workers from 33 manufacturing companies were enrolled in the study.The sectors of activity of the surveyed companies were food and beverages (14 companies), minerals (6 companies) and textiles (13 companies).Thirteen companied were small-sized, 14 midium-sized, and 6 large-sized.There were no refusals to participation in the study and there were no missing or incomplete data.  1 presents the descriptive statistics of the study sample, as well as the estimates derived for the target population using sampling weights and the characteristics of the survey design (two-stage clustered sampling and stratification).The population of manufacturing workers had a mean age of 38.6 years, 53.6% were males, 62.6% lived with a companion, the average income was 1.53 minimum wages, the average body mass index was 27.4, 33.2% had normal weight, 38.2% were overweight and 27.5% were obese.
Table 2 presents indicators of the daily consumption of MSM.About 29% of the population (95%CI 24.5%-33.5%)include MSM in the diet, at an average daily intake of 65.7 g, corresponding to a daily total of 202.5 kcal.Kilocalories from MSM represent 9.95% (95%CI 8.68%-11.2%) of total daily caloric intake, and nearly half (47.3%) of daily kcal from ultra-processed (UP) products comes from MSM.
Table 3 presents, for each socioeconomic characteristic of the subjects, the prevalence of MSM consumption, the consumption of MSM as percent contribution to total daily calories, and as percentage of the total calories from UP products.Persons with lower literacy incorporate a greater amount of MSM in their diet (p = 0.05) and in their share of UP products (p = 0.04).Male workers may have greater tendency to consume MSM products, but the difference did not quite reach statistical significance (p = 0.06).Increased consumption of MSM is also associated with younger age (odds-ratio 0.970, p = 0.004) but neither with BMI (odds-ratio 1.009, p = 0.62) nor waist circumference (WC) (odds-ratio 1.007, p = 0.37).Age correlates with percent contribution of total caloric intake (regression coefficient − 0.070, p = 0.007), but no correlation was found with BMI (regression coefficient 0.054 p = 0.28) and WC (regression coefficient 0.013, p = 0.49).Neither variable was correlated with percent contribution of total UP consumption (regression coefficients: age − 0.213, p = 0.07; BMI 0.273, p = 0.28; WC 0.090, p = 0.31).In multivariate analysis, age (OR 0.964, p = 0.002) and waist circumference (OR 1.017, p = 0.05) were associated with MSM consumption.The variables independently associated with MSM percent contribution to total calorie intake were age (regression coefficient − 0.089, p = 0.002) and lower education (regression coefficient 1.569, p = 0.01).In multivariate analysis the variables associated with MSM percent contribution to total UP Kcal consumption, were age (regression coefficient − 0.294, p = 0.020) and lower education (regression coefficient 6.560, p = 0.012).
Table 5 shows the food products containing MSM that are most consumed, both as total daily energy and as percent of total MSM consumption.Sausages and frankfurters are the preferred products, each representing over one-third of MSM products consumption.
Table 6 presents the comparison, between MSM consumers and non-consumers, of the consumption of food products from NOVA classes of level of processing.MSM consumers showed a lesser intake of unprocessed or minimally processed foods (p < 0.001), and a higher intake of ultra-processed foods and drink products (p < 0.001).
Table 7 presents the difference between consumers and non-consumers of MSM in the composition of the diet, expressed as percent of total energy intake of food groups defined according to their nature and nutritional profile.Food groups representing less than 1% of total energy intake are not shown.MSM consumers have increased intake of corn (p = 0.001) and processed meats (p < 0.001), and lesser intake of tubers and roots (p = 0.017), fruits (p = 0.015), white (p > 0.001) and red meat (p = 0.004), and eggs (p = 0.006).

Discussion and conclusions
To the best of our knowledge, this is the first study analyzing the consumption of MSM in the population.The results of this study on Brazilian manufacturing workers have shown that MSM consumption represents around 10% of individuals' total daily caloric intake, and almost half of the daily kcal from ultra-processed products (UP).Its consumption is greater among younger people, people with lower education, and possibly also in males.Individuals who consume MSM have greater consumption of energy, carbohydrates, fats (total, saturated, monounsaturated and omega-6 fatty acids), sodium and fiber.Their dietary patterns are characterized by lower consumption of in natura foods or minimally processed foods, such as tubers and roots, fruits, white and red meat and eggs, and greater consumption of ultra-processed foods and beverages.The MSM most consumed were sausages and frankfurters.
This type of meat product is only present in ultra-processed foods (within the group of processed meats), and in this study we observed that MSM correspond to almost half of UP consumption.Therefore, knowing that the consumption of UP, which already has a big expression in high-income developed countries and has been increasing rapidly in middle-income countries such as Brazil 36 , an increasing trend in the consumption of MSM can be implied.
The explanations for the differences in MSM consumption between sexes, age groups and education may be because, being a UP food, MSM is likely to be mostly consumed by individuals who also have UP foods in their dietary habits, and studies have shown that UP consumption is related to younger age and male sex 37 .Socioeconomic inequality, including a lower educational level, may lead to a preference for less expensive, less nutritious foods 38 .No studies have yet investigated variables associated with the consumption of MSM, but the literature on the broader class of UP foods confirms our findings.In a study in Canada, with around 19 thousand adults and with a similar methodology to our study (24HR as a dietary survey), the consumption of UP foods www.nature.com/scientificreports/(class in which MSM are present) was higher among men, younger adults, and those with fewer years of formal education 39 .In addition to this study, a systematic review of the global consumption of UP foods observed high variability based on sex and age, with men and young people generally showing higher levels of consumption compared to older individuals 38 .
It is worth mentioning that, in our results, when controlling by age, greater consumption of MSM was also related to greater waist circumference.Waist circumference is strongly associated with all-cause and cardiovascular mortality [40][41][42] and is used for cardiovascular risk classification.Consumption of processed meat has also been associated with negative health outcomes, as shown by a meta-analysis of nine prospective cohort studies www.nature.com/scientificreports/ that estimated that each daily portion of processed meat (the group in which MSM is included) was associated with a 15% increase in the risk of all-cause and cardiovascular mortality 43 .Consequently, it is necessary to give more attention to the nutritional composition of foods based on MSM.To the best of our knowledge, this is the first study that analyzed nutrients and energy consumption through nutritional analysis.In our results, we have seen a relationship between greater consumption of MSM and greater intake of calories, fats (including total, saturated, monounsaturated and omega-6), carbohydrates and sodium.Furthermore, MSM is not equivalent to manually boned meat.A study evaluating the chemical composition of MSM through density measurements, found that manually boned meat, in relation to all types of MSM, is characterized by higher density, higher protein content and lower sodium, calcium and fat content 2 .Therefore, replacing manually boned meat with MSM cannot be justified as an improvement in nutritional composition.In some parts of the world, such as the European Union, products of animal origin represent 58% of the availability of proteins per capita/day, and meat products constitute the main source of proteins (28 g of protein/person/ day), corresponding to 30% of total caloric consumption 44 .These data make us think about the consequences of replacing minimally processed animal proteins with MSM, as was seen in in the present study, where a reduction in the consumption of red and white meat and eggs was seen in individuals who consume more MSM, as the characteristics and protein content contained in MSM are not similar to those in unprocessed or minimally meat or in eggs.www.nature.com/scientificreports/It was also observed in this study that individuals who consume more MSM, in addition to lower consumption of minimally processed animal proteins also have lesser consumption of unprocessed foods, such as fruits, roots and tubers.This demonstrates a tendency towards greater consumption of processed foods in general.We have also found that MSM consumers have greater consumption of corn, which most likely is due to the preparations that accompany some MSM products, namely sausages and frankfurters, such as regional dishes based on corn couscous, widely consumed in the northeast of Brazil.This is an example of the insertion of MSM into traditional culinary preparations and its potential advancement in the population's eating habits.
Therefore, given all this potential for commercial expansion of MSM, further studies are needed to analyze the impact of its consumption on the population so that it can be promoted and alert to the need to implement new regulations and inspections, which are still scarce due to the lack of knowledge related to this type of food product, both by the scientific community, the society, and the consumers.Little evidence has analyzed its nutritional aspects and effects on health and food consumption, but it is known that this type of product falls within the group of ultra-processed foods, which are widely related to unfavorable health outcomes 45 .
This study has some limitations, such as having been carried out in a single federation state.As the survey was conducted on the population of manufacturing workers, the estimates may not be readily generalizable to other populations.The strengths of our study include it being based on a representative sample of the population obtained with a complex survey design, large sample size, no subject dropouts or refusals to participation, direct interviews by trained nutritionists, and design-based analysis incorporating survey weights.
The results of this study show an association between the consumption of MSM with higher intake of energy, carbohydrates, fats, and sodium, as well as with higher intake of UP products and lower intake of minimally processed/in natura foods.There is tendency for the substitution of protein from unprocessed sources by MSM products and, although they do not have the same nutritional characteristics, their affordable prices combined with a lack of technical information related to quality, have already made them part of the population's dietary habits.

Table 1 .
Characteristics of the study sample and population estimates.Tabulated values are mean ± standard deviation, or number(percent).

Table 2 .
Indicators of consumption of Mechanically separated meats (MSM).

Table 3 .
Determinants of consumption of mechanically separated meats (MSM).Significants values are in bold.

Table 4 .
Daily intake of nutrients in non-consumers and consumers of mechanically separated meats (MSM).Significants values are in bold; CI: confidence interval.

Table 6 .
Consumption of NOVA class in percentage of total energy intake.Significants values are in bold; MSM: mechanically separated meat; S.E.: standard error; CI: confidence interval.

Table 7 .
Consumption of food groups in percentage of total energy intake.Significants values are in bold; MSM: mechanically separated meat;.S.E.: standard error; CI: confidence interval.